docs: def to_polygon(self, radius):
          """
          Create a circular polygon with specified radius centered in the point.
  
          :param radius:
              Required radius of a new polygon, in km.
          :returns:
              Instance of :class:`~openquake.hazardlib.geo.polygon.Polygon` that
              approximates a circle around the point with specified radius.
          """
          assert radius > 0
          # avoid circular imports
          from openquake.hazardlib.geo.polygon import Polygon
  
          # get a projection that is centered in the point
          proj = geo_utils.OrthographicProjection(
              self.longitude, self.longitude, self.latitude, self.latitude)
          
          # create a shapely object from a projected point coordinates,
          # which are supposedly (0, 0)
          point = shapely.geometry.Point(*proj(self.longitude, self.latitude))
      
          # extend the point to a shapely polygon using buffer()
          # and create openquake.hazardlib.geo.polygon.Polygon object from it
          return Polygon._from_2d(point.buffer(radius), proj)